Having developed a real time audio-cum-visual Doppler-shifted ultrasound monitoring device, we intend (1) to evaluate its diagnostic potential for monitoring blood-flow in deeply-situated arteries, eg., aorta, renal, hepatic, by means of vascular responses to various stimuli and in the presence of induced disease states. (2) To continue in vitro wave-form analysis using a pulsatile flow fluid system analogue. (3) To evaluate its transcutaneous application by means of pulsed Doppler ultrasound. This will be done (a) by locating vessels by an ultrasound B scanner and focussing the pulsed echo on to them. (b) By attempting to obtain a signal from the parenchyma of the organ they supply which preliminary studies suggest may be possible. The latter two approaches are natural developments resulting from experience to date.